Decay Definition and 998 Threads

I'm skeptical about a some things in physics as some things are hard to understand, or I need to see proof to believe it. I find that for physics, it helps a lot to see a real life demonstration (video) of what's being explained. I understand the whole radioactive decay thing, but I have not...

Homework Statement I am a freshman in physics, just done a lab about radioactive decay. I've measured the # of beta particles per second 400 times and got the frequency of each number K using Excel. I'm supposed to take the data and fit it to a puason distribution in MATlab. The data points...

hey guys! I'm really confused as to what this question is trying to ask me! can someone help me out :) Air pressure decays approximately exponentially at about 0.4 per cent for each rise of 30 metres above sea level. If we let p = p(h) denote air pressure (measured in some appropriate units) at...

In euclidean quantum field theory, the imaginary part of the free energy, defined as the logaritm of the partition function, is it connected to the decay rate?

p -> e+ + pi° is >10^33 years. what conservation law does this limit test? p is uud pi° is uu or dd where the second quark of each is an antiquark baryon number is not conserved 1 = 0 + 0 charge is conserved lepton number is not conserved 0 = -1 + 0 not sure what this...

Hawking Radiation and the "Decay" of Black Holes I have been doing a lot of reading and thinking about certain quantum mechanics so that I can try and wrap my head around how it all works. However I have come upon something that I cannot find a good explanation for. I was reading about...

In a metal, can one electron decay into one lower-energy electron plus one phonon? (i.e., can the attached Feynman diagram occur?) If we replace phonons by photons and consider the process in a vacuum, I guess this is prohibited because you can always boost to a frame where the incoming and...

I have a really basic question about radioactive decay. If it takes 4.4 billion years for uranium-238 to decay into thorium-234, how can the decay rate be measured? What intermediate activity is taking place that would give an indication of the time it would take an atom to decay into the next...

[Mentor's note: this thread does not use the standard homework-help template, because it was started in one of the non-homework forums. It was moved here because it had already gotten some help.] Hi everyone. This isn't a homework question, as I am just revising notes for my exams, and after...

Hi all, I think that the off shell decay dosn't decrease the decay cross section, I mean if a particle X decays into a jet pair has mass for example Mjj ~ 130 GeV, being X has mass M ~ 130 GeV so decay in resonance or on shell into jj or being MX even much greater ~ 2000 GeV , this...

Write down a reaction by which a K+ can be produced in a proton-proton collision and give the quark content of each particle involved. Conservation of energy, charge, baryon number, lepton number, strangeness and isospin How do I go about doing this? it has already given the p + p...

The answer is not provided by AAPT. Homework Statement A mixture of ^{32}P and ^{35}S (two beta emitters widely used in biochemical research) is placed next to a detector and allowed to decay, resulting in the data (attached) below. The detector has equal sensitivity to the beta particles...

All nuclei with A > 210 are alpha emitters, yet very few emit protons spontaneously. Yet both decays lower the Coulomb energy of the nucleus. Why is proton decay not more common?

"Radium-226 has a half-life of 1,620 years, which means that half of a given sample of radium-226 will decay into lead by the end of 1,620 years. In the next 1,620 years, half of the remaining sample will decay into lead, leaving one-fourth of the original amount of radium-226."(1) Wouldn't...

Homework Statement Ok, so I need to make a software that will simulate a neutral kaon system, and I only have the following data about the masses and decay widths: gammaS = 580*gammaL {S = short lived state, L = long lived state} mS - mL = 0.477*gammaS Homework Equations How...

What is the Decay Width of a particle and how is it related to the particle's lifetime ?

I saw the thread called Decay/Reactivity of DMSO and it was closed. Since the thread was inconclusive I have decided to share my results. After approximately 18 years my 99.9% DMSO has completely decayed. When this happens it will no longer crystallize in the refrigerator. It will lose all...

Homework Statement I am having issues with some problems relating to a plant theoretically shut down on natural circulation, and calculating the core ΔT and natural circulation flow rate.. Can anyone provide some equations or theory I could use to assist me? I'm not familiar with this...

I would like to ask will the daughter of a decayed particle carries net charge? For example, after beta negative decay will the daughter atom carries net positive charge and in an alpha decay the daughter carries net negative charge? I search many textbooks and none of them mention about the...

So i have a question regarding a homework question I'm working on which suggest a neutral pion traveling with velocity v decays into two gamma rays of equal theta to the normal and they of course have velocity c. It then asks to prove that v= cos theta Which kind of confuses me. I mean if...

When modelling exponential decay in class we did a water flow through a burette experiment. We were given the equation V(t)= V0 e^-λt and ln(V0/V)=λt Where lambda is the decay constant, V0 is the initial volume and V is the volume at any time t. What does the decay constant actually tell you in...

Homework Statement A plutonium-239 nucleus at rest decays into a uranium-235 nucleus by emitting an alpha particle (4He) with kinetic energy of 5.15 MeV. Find the speed of the uranium nucleus. The Attempt at a Solution How should I approach this problem? m1v1=-m2v2

Hi, I'm in the process of revision for upcoming exams, one likely question will give a number of decays (~5) and ask if they are possible. I understand baryon number, lepton number (and parity, isospin, and strangeness) must be conserved, but for example for the following: K+ -> neutral...

A spin 1/2 particle A undergoes decay A→B+C+D Where it is known that B and C are also spin 1/2. The complete set of allowed values of spin of D It was a Multiple Choice Question and options given were 1) 1/2,1,3/2,2,5/2,3,... 2) 0,1 3) 1/2 only 4) 1/2,3/2,5/2,7/2,... I tried the...

Homework Statement If all of the energy from decay of the 40-K in one banana could be captured and converted into electrical energy, how many bananas would be needed to power a 100 W light bulb? There is 358 mg potassium-K per 100 grams of banana half life of potassium-40 is...

Hi, i am new here. Thought it would be good to sign up as i have just started hitting the books in preparation for my AS Level exams. So this is my first question. I think i may have done this question correctly, but i was just seeing what other people think as i am not 100% sure about it...

Homework Statement If you have 500g of Thorium-234 at t=0. Calculate the initial activity and the activity after 2 weeks. The half life of thorium-234 is 24 days. Homework Equations A=A_0e^{-\lambda t} \\ A_0=\lambda N_0 \\ \lambda=\frac{ln2}{t_{\frac{1}{2}}} The Attempt at a Solution For the...

Homework Statement Consider an item that is initially sold at a market price of $10 per unit. Over time, market forces push the price toward the equilibrium price, $20, at which supply balances demand. After 6 months, the price has increased to $15. the Evans Price Adjustment model says that...

Homework Statement Suppose water leaks out of a barrel at a rate proportional to the square root of the depth of the water. If the level starts at 36 in. and drops to 35 in. after 1 hour, how long will it take for all the water to leak out of the barrel? I have to choose and implement a...

In beta decay, is the W boson created by the change of a quark or does it cause the change? Also, I don't fully understand where the W bosons come from or how they are created. If someone could please explain this to me, I'm very confused.

Hello all you physics folks, this is my first post, so if I screw this up, go easy on me :) Here's the problem I'm working on and that I simply can't get my head wrapped around: I have a table of 10 values of counts per second (cps) of alpha decay of Americium-241, depending on the...

In the process of particle decay (eg carbon-14 ---> nitrogen-14), is there any relations with radioactivity? Is it reversible? ( up quark + 2 x down quark + W positive boson = down quark + 2 x up quark + electron, so that carbon-14 turns to nitrogen-14. Is it possible that down quark + 2 x up...

Homework Statement A small quantity of the thorium isotope Th(A=228, Z=90) (half-life 1.913 y) is prepared and electroplated onto a thick sheet of copper and overcoated with a thin film of gas-tight polymer. The plating and coating are both thin enough so that none of the alpha particles...

Figured this was more a chemistry question than nuclear question, so I put it here. When an atom of tritium in ^{3}_{1}H_{2}O decays, it becomes ^{3}_{2}He^{1+} + e^{-} + ^{3}_{1}HO This then quickly becomes ^{3}_{2}He + ^{3}_{1}HO I'm a little confused about the hydroxide. It needs...

Hi, Given the initial energy of a pion is it possible to calculate the probability and mode of its decay? Ive looked everywhere for a relevant formula but everywhere simply states the probability and mode... Wiki "The primary decay mode of a pion, with probability 0.999877, is a purely...

The formula for radioactive decay over time is N = N0eλt . The formula for how many number of atoms counted by the Geiger as distance (x) changes is C = k/x2. How can I merge these formulas to give one that accounts for distance and time? Secondly, how does the second formula work...

Homework Statement Knowing the decay constant ##\lambda## of a nucleus, find the probability of the decay of the nucleus during the time from 0 to ##t##. Homework Equations The Attempt at a Solution I don't know where to start from. I know that the decay is first order and the...

Consider our universe but with only two particles, say two protons. Inevitably they would orbit mutually about one another. As such, the time evolution of this trivial system would be cyclic, forever repeating their monotonous movement. This suggests that time is not absolute. It may not even be...

Tunneling from Rectangular barrier - Exponential Decay ?? Consider the Rectangular Potential Barrier. If one solves bound state Problem in this case, wavefunctions of Exponentially Decaying and rising kind are found for the Region in the Barrier. ψ = A eαx + B e-αx Yet Most Books and...

Apologies, this is going to be a bit disjointed, I don't want to write the full question down as I don't want anyone to give me a solution as its an assignment question. 1. am i correct in assuming when a pion decays at rest its energy will be given by: E^2 = p^2 c^2 + m^2 c^4 which...

first, is my initial understanding correct that each isotope go for only a particular kind of decay? and if so, why? What makes uranium-238 go only for an alpha decay? while uranium 235 go for a fission decay?

Would someone please tell me how I would show Strontium-90 decay into Yttrium 90(and emitting Beta particles)? Would I need to use a Feynman diagram? Thank you!

Hi there, When an alpha particle is formed inside a nucleus by binding together is this essentially nuclear fusion occurring? Why is this more likely to happen in a large nucleus than a small one? Thanks

Particle Physics -- decay of a neutral pion Homework Statement Consider the decay of a neutral pion that has a momentum of 10 GeV/c into two photons. What is the minimum energy that a photon from this decay can have? In terms of the pion mass and pion momentum. What about Maximum Energy...

I am trying to learn what a Beta+ decay really is, and I don't really understand. For instance, how on Earth can a proton be turned into a neutron, when it has less mass? Someone once told me that in a Beta+ decay 511 kev is being emitted in forms a electromagnetic light. Is it those "511...

I am trying to understand an equation that I found in an old document concerning pressure decay of a sealed assembly. The assembly is pressurized and over time decays to 1 atmosphere ambient pressure. The equation P = (P1-P0)e(-(A/V)t) + P0 is used but not all the terms are defined P =...

Hi i can't understand why is the positron in Feynmans diagram is going towards the w+ boson and not outward, i have a problem understanding why this is happining for beta minus decay also the antielectron neutrino is also going towards the reaction of the w- boson

Hi, I am drawing Feynman diagrams for various Higgs decay channels. There are two diagrams I am stuck on and there aren't many examples online. They are H→gg and H→Z\gamma For the H→gg decay I had a stab at drawing the reverse of the gluon fusion diagram. Higgs decaying to two gluons via a...

Homework Statement Hey guys, so I'm new to Feynman diagrams, and I have a few to draw but i'll start with the first one. I'm being asked to draw the following process: \pi^{0}(uu* or bb*)→\gamma +\gamma. I have to "clearly label each quark, lepton and boson, and say which fundamental force...

Homework Statement We are the given the rare decay: π+ → e+ + ve Also, we are given mπ = 139.6 MeV/c2, mv ≈ 0, me+ = 0.511 MeV/c2 And we are given that the decay starts with the pion at rest, so I took that to mean that pπ = 0 Solve for the momentum of the positron. Homework Equations...